Index: src/org/openstreetmap/josm/io/AbstractReader.java
===================================================================
--- src/org/openstreetmap/josm/io/AbstractReader.java	(revision 17076)
+++ src/org/openstreetmap/josm/io/AbstractReader.java	(working copy)
@@ -622,7 +622,11 @@
 
     protected OsmPrimitive buildPrimitive(PrimitiveData pd) {
         OsmPrimitive p;
+        long id = pd.getUniqueId();
         if (pd.getUniqueId() < pd.getIdGenerator().currentUniqueId()) {
+            if (id <= -101747) {
+                long dd = 4;
+            }
             p = pd.getType().newInstance(pd.getUniqueId(), true);
             pd.getIdGenerator().advanceUniqueId(pd.getUniqueId());
         } else {